All-fibre phase filters with 1-GHz resolution for high-speed passive optical logic processing

Photonic-based implementation of advanced computing tasks is a potential alternative to mitigate the bandwidth limitations of electronics. Despite the inherent advantage of a large bandwidth, photonic systems are generally bulky and power-hungry. In this respect, all-pass spectral phase filters enable simultaneous ultrahigh speed operation and minimal power consumption for a wide range of signal processing functionalities. Yet, phase filters offering GHz to sub-GHz frequency resolution in practical, integrated platforms have remained elusive. We report a fibre Bragg grating-based phase filter with a record frequency resolution of 1 GHz, at least 10x improvement compared to a conventional optical waveshaper. The all-fibre phase filter is employed to experimentally realize high-speed fully passive NOT and XNOR logic operations. We demonstrate inversion of a 45-Gbps 127-bit random sequence with an energy consumption of similar to 34 fJ/bit, and XNOR logic at a bit rate of 10.25 Gbps consuming similar to 425 fJ/bit. The scalable implementation of phase filters provides a promising path towards widespread deployment of compact, low-energy-consuming signal processors.

Automated summary

Photonic-based implementation of advanced computing tasks is a potential alternative to overcome the limitations of electronics in terms of bandwidth. Despite their large bandwidth advantage, photonic systems are generally bulky and consume high power. In this study, we presented a fiber Bragg grating-based phase filter with a record frequency resolution of 1 GHz, which is a significant improvement compared to conventional optical waveshapers. The demonstrated high-speed passive logic operations using the all-fiber phase filter show promising potential for compact and low-energy-consuming signal processors.